University of the Highlands and Islands
Outer Hebrides

Globally, approximately 1.2 billion people lack access to safe drinking water services and approximately 2.4 billion people lack access to sanitation. Safe and readily available potable water is vital for health in terms of drinking water, sanitation, domestic use and food production, alongside economically beneficial commercial and industrial activities. The two main desalination technologies are thermal desalination and reverse osmosis (RO). Thermal desalination technology is well-established in the Middle East and, whilst a typical thermal desalination plant uses more energy than a comparable RO plant, it is more robust than RO systems and potentially less harmful to the environment. Hence, well-designed thermal desalination plant, powered by renewable energy sources, can produce water sustainably and efficiently from seawater. The specific salinity of a water source has a significant effect on the size and design of the required desalination plant but the influence of water salinity and composition on thermal desalination rate and fouling is not fully understood. By undertaking pool boiling experiments across the whole range of salinities, physical validation of the various extant deposition theories can be made. Slip ratio, which is the ratio of gas phase velocity to liquid phase velocity, will be investigated in pool boiling conditions for the first time. In turn, this will allow more effective and efficient design and service planning. Studies on energy modelling for thermal desalination are limited and, to my knowledge, none incorporate both hydrogen storage and seawater heat pumping. I therefore propose to model and optimise a hybrid wind-solar energy system incorporating seawater heat pumping and hydrogen energy storage. Hybrid wind-solar energy systems are typically more cost-effective and reliable than single- source systems. Seawater heat pumping reduces the energy required for desalination. Energy storage in gaseous hydrogen form avoids the environmental issues associated with battery production and disposal.